package com.jt.www.common.service.zqsign.dependency;

import org.springframework.security.crypto.codec.Base64;

import java.io.*;


/**
 *
 */

/**
 * <p> 
 * BASE64编码解码工具包 
 * </p> 
 * <p> 
 * 依赖javabase64-1.3.1.jar 
 * </p> 
 *
 * @author IceWee
 * @date 2012-5-19 
 * @version 1.0
 */
public class Base64Utils {

    /** */
    /**
     * 文件读取缓冲区大小 
     */
    private static final int CACHE_SIZE = 1024;

    /** */
    /**
     * <p> 
     * BASE64字符串解码为二进制数据 
     * </p> 
     *
     * @param base64
     * @return
     * @throws Exception
     */
    public static byte[] decode(String base64) throws Exception {
        return Base64.decode(base64.getBytes());
    }

    /** */
    /**
     * <p> 
     * 二进制数据编码为BASE64字符串 
     * </p> 
     *
     * @param bytes
     * @return
     * @throws Exception
     */
    public static String encode(byte[] bytes) throws Exception {
        return new String(Base64.encode(bytes));
    }

    /** */
    /**
     * <p> 
     * 将文件编码为BASE64字符串 
     * </p> 
     * <p> 
     * 大文件慎用，可能会导致内存溢出 
     * </p> 
     *
     * @param filePath 文件绝对路径 
     * @return
     * @throws Exception
     */
    public static String encodeFile(String filePath) throws Exception {
        byte[] bytes = fileToByte(filePath);
        return encode(bytes);
    }

    /** */
    /**
     * <p> 
     * BASE64字符串转回文件 
     * </p> 
     *
     * @param filePath 文件绝对路径 
     * @param base64 编码字符串 
     * @throws Exception
     */
    public static void decodeToFile(String filePath, String base64) throws Exception {
        byte[] bytes = decode(base64);
        byteArrayToFile(bytes, filePath);
    }

    /** */
    /**
     * <p> 
     * 文件转换为二进制数组 
     * </p> 
     *
     * @param filePath 文件路径 
     * @return
     * @throws Exception
     */
    public static byte[] fileToByte(String filePath) throws Exception {
        byte[] data = new byte[0];
        File file = new File(filePath);
        if (file.exists()) {
            FileInputStream in = new FileInputStream(file);
            ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
            byte[] cache = new byte[CACHE_SIZE];
            int nRead = 0;
            while ((nRead = in.read(cache)) != -1) {
                out.write(cache, 0, nRead);
                out.flush();
            }
            out.close();
            in.close();
            data = out.toByteArray();
        }
        return data;
    }

    /** */
    /**
     * <p> 
     * 二进制数据写文件 
     * </p> 
     *
     * @param bytes 二进制数据 
     * @param filePath 文件生成目录 
     */
    public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
        InputStream in = new ByteArrayInputStream(bytes);
        File destFile = new File(filePath);
        if (!destFile.getParentFile().exists()) {
            destFile.getParentFile().mkdirs();
        }
        destFile.createNewFile();
        OutputStream out = new FileOutputStream(destFile);
        byte[] cache = new byte[CACHE_SIZE];
        int nRead = 0;
        while ((nRead = in.read(cache)) != -1) {
            out.write(cache, 0, nRead);
            out.flush();
        }
        out.close();
        in.close();
    }

    /**
     * 输入流转byte字节
     * @param inStream
     * @return
     * @throws IOException
     */
    public static byte[] input2byte(InputStream inStream) throws IOException {
        ByteArrayOutputStream swapStream = new ByteArrayOutputStream();
        byte[] buff = new byte[100];
        int rc = 0;
        while ((rc = inStream.read(buff, 0, 100)) > 0) {
            swapStream.write(buff, 0, rc);
        }
        byte[] in2b = swapStream.toByteArray();
        return in2b;
    }


}  